spring and ejb 3: all-star team or neighbors with good fences

Spring and EJB 3: All-Star Team

or Neighbors with Good Fences

Debu Panda

Author: EJB 3 In Action

EJB 3 and Spring

•EJB darling of industry!

•Every application must have EJB ☺☺☺☺

Dot Com Boom (J2EE 1.2/1.3)

• Hangover of EJB

overdose over

• Lightweight frameworks appeared

to simplify complexities of

enterprise Java!

• Lightweight frameworks rule the world!

• EJB reinvented as POJO!

• Scripting Languages

and .Net challenge supremacy of Java

• Can EJB 3 be savior

for Java EE!

Java EE and frameworks: State of Nation

Dot Com Bubble burst (J2EE 1.4) Now! (Java EE 5)

EJB 3 : Produces Two Specs

Simplified Development with EJB 3

• POJO (Plain Old Java Object) Class

— EJB Class is a plain java class

• POJI (Plain Old Java interface)

— Regular business interface

— EJB interface does not have to implement EJB specific API

• No need of home interface

• Annotations for type of EJB and interface

• Deployment descriptor is optional

EJB 3 : Simplifying with annotations

@Stateless

@Stateful

@MessageDriven

EJB 3 Example

@Stateless

public class PlaceBidBean implements PlaceBid {

…

public Long addBid(Bid bid) {

..

}

}

Example Spring Bean

public class BidServiceBean implements BidService {

..

public Long addBid(Bid bid){}

}

<bean id="bidService" class="actionbazaar.buslogic.BidServiceBean">

<property name="bidEAO">

<ref bean="bidEAO"/>

</property>

…

</bean>

EJB 3 and Spring Feature Sets

Poor direct support, best integration available is via configuring

XFire for registered beans.

Seamless support for JAX-WS 2.0Web services

Must add and configure Acegi security. However, support beyond

JAAS is possible through Acegi.

Integrated support for declarative and programmatic security

through JAAS.

Security

Must add and configure Quartz for scheduling.Simple scheduling possible through EJB Timer service.Scheduling

Can inject almost anything including lists, maps, properties and JNDI

resources

Constructor and setter

Can inject anything in the container including EJBs, data

sources, JMS resources, JPA resources and web services

endpoints.

Field and Setter

No standard solution for injecting regular POJOs

Dependency Injection

Robust support through AspectJ.Simple but limited support through interceptors.AOP

Remoting support may be added via configuration. Remote transactions and security are not supported. However protocols

other than RMI such as Hessian and Burlap are supported.

Integrated support through Session Bean remote interfaces. Supports distributed transactions and security.

Remoting

Need to add configuration for each message listener. However, JMSTemplate and MessageListenerAdapter add nice abstraction.

Supported out of the box through Message Driven Beans.Messaging

Indirect support dependent on web container session managementRobust support through Stateful Session Beans and

Extended Persistence Context

State management

Framework support for JPA, Hibernate, TopLink, JDBC, iBatisTightly integrated through JPAPersistence

Have to configure it to make it work, but supports a number of

strategies including JTA, JDBC and Hibernate

Works right out of the box, but only JTA is supportedTransaction management

SpringEJB 3

EJB 3 with JPA

@Stateless


@PersistenceContext

private EntityManager entityManager;

@TransactionAttribute(TransactionAttributeType.REQUIRED)

public void addBid(Bid bid) {

entityManager.persist(bid);

}

}

@Local

public interface PlaceBid {

void addBid(Bid bid);

}

JPA with Spring

public class BidServiceBean implements BidService {

protected BidEAO bidEAO ;

public void set BidEAO(BidEAO bidEAO) {

this.bidEAO = bidEAO;

}

public Long addBid(Bid bid){

return this.bidEAO.saveBid(bid).getBidId();

}

public class BidSpringEAO extends BasicSpringEAOimplements BidEAO {

public void persistBid(Bid bid) {

…

this.getJpaTemplate().saveBid(bid);

}

• Integrated with JPA to use container-managed EntityManager

• Provides further simplification with JpaTemplate

• Ships TopLink Essentials as default JPA provider

Spring Configuration

<bean id="entityManager"

class="org.springframework.jndi.JndiObjectFactoryBean">

<property name="jndiName">

<value>java:comp/env/actionBazaar</value>

</property>

..

</bean>

<bean id="bidService" class="actionbazaar.buslogic.BidServiceBean">

<property name="bidEAO">

<ref bean="bidEAO"/>

</property>

</bean>

<bean id="bidEAO"

class="actionbazaar.persistence.eao.BidSpringEAO"

autowire="byType">

<property name="entityManager" ref="entityManager"/>

</bean>

EJB 3 Transactions

@Stateless

@TransactionManagement(TransactionManagementType.CONTAINER)


..




}

}

• Natively integrated with JTA Transaction Manager

• Bean or Container managed

Transactions with Spring

@Transactional(propagation=Propagation.REQUIRED)

public Long addBid(Bid bid){

..

}

<tx:annotation-driven/>

<bean id="transactionManager" class=

"org.springframework.transaction.jta.OC4JJtaTransactionManager">

</bean>

• Proprietary integration with JTA Transaction Manager of

application servers (Oracle, BEA, IBM)

• May use other local transaction managers

EJB 3 Web service

@Stateless

@WebService


@PersistenceContext

private EntityManager entityManager;


@WebMethod



}

}

Spring Configuration for a Web service

<bean class="org.springframework.remoting.rmi.RmiServiceExporter">

<property name="serviceName" value="placeBid"/>

<property name="service" ref="placeBid"/>

<property name="serviceInterface" value="PlaceBid"/>

<property name="registryPort" value="1199"/>

</bean>

<bean id="placeBidService" class="org.codehaus.xfire.spring.remoting.XFireExporter">

<property name="serviceFactory" ref="xfire.serviceFactory"/>

<property name="xfire" ref="xfire"/>

<property name="serviceBean" ref="placeBid"/>

<property name="serviceClass" value=”PlaceBid”/>

</bean>

..

Spring Configuration for a Web service

…

<bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">

<property name="urlMap">

<map><entry key="/PlaceBidService">

<ref bean="placeBidService"/></entry>

</map>

</property>

</bean>

EJB 3 State management

@Stateful

public class BidderAccountCreatorBean implementsBidderAccountCreator {

@PersistenceContext(type=PersistenceContextType.EXTENDED) private EntityManager entityManager;

public void addLoginInfo(LoginInfo loginInfo) {

entityManager.persist(loginInfo);

}

@Remove

public void createAccount() {

entityManager.flush();

}

}

No state management support with Spring

EJB 3 Dependency Injection Examples

@EJB AdminService bean; public void privilegedTask() {

bean.adminTask();

}

@Resource(name=”myDB”)public void setDataSource(DataSource myDB) {customerDB = myDB;

}

@WebServiceRef(wsdlLocation= "http://ejb3inaction.com/webservice/PlaceBidService?WSDL")private PlaceBidService bidservice;

Dependency Injection in Spring

<bean id="placeBid" class="PlaceBidBean">

<property name="bidDao" ref="bidDao"/>

<property name="dataSource">

<jee:jndi-lookup jndi-name="jdbc/ActionBazaarDB"/>

</property>

<property name="concurrencySensitivity" value="1"/>

<property name="adminEmails">

<props>

<prop key="administrator">

[email protected]

</prop>

<prop key="support">

[email protected]

</prop>

</props>

</property>

</bean>

AOP in Spring

@Aspect

public class AuditAspect {

@Before("execution(public * *(..)) && @annotation(Auditable)")

public void audit(JoinPoint joinPoint) {

System.out.println("Entering: " + joinPoint);

System.out.println(" with args: " +joinPoint.getArgs());

}

}


..

@Auditable


sessionFactory.getCurrentSession().save(bid);

}

}

Poor man’s AOP in EJB 3: Interceptor

public class ProfilingInterceptor {

@AroundInvoke // mark this method as a beaninterceptor

public Object checkPermission(InvocationContextctx) throws Exception {

System.out.println("*** checkPermissioninterceptor invoked");

… }

}

@Stateless

@Interceptor({oracle.ejb30.ProfilingInterceptor.class})


}

Review : EJB 3 and Spring Feature Sets

Poor direct support, best integration available is via configuring

XFire for registered beans.

Seamless support for JAX-WS 2.0Web services

Must add and configure Acegi security. However, support beyond

JAAS is possible through Acegi.

Integrated support for declarative and programmatic security

through JAAS.

Security

Must add and configure Quartz for scheduling.Simple scheduling possible through EJB Timer service.Scheduling

Can inject almost anything including lists, maps, properties and JNDI

resources

Constructor and setter

Can inject anything in the container including EJBs, data

sources, JMS resources, JPA resources and web services

endpoints.

Field and Setter

No standard solution for injecting regular POJOs

Dependency Injection

Robust support through AspectJ.Simple but limited support through interceptors.AOP

Remoting support may be added via configuration. Remote transactions and security are not supported. However protocols

other than RMI such as Hessian and Burlap are supported.

Integrated support through Session Bean remote interfaces. Supports distributed transactions and security.

Remoting

Need to add configuration for each message listener. However, JMSTemplate and MessageListenerAdapter add nice abstraction.

Supported out of the box through Message Driven Beans.Messaging

Indirect support dependent on web container session managementRobust support through Stateful Session Beans and

Extended Persistence Context

State management

Framework support for JPA, Hibernate, TopLink, JDBC, iBatisTightly integrated through JPAPersistence

Have to configure it to make it work, but supports a number of

strategies including JTA, JDBC and Hibernate

Works right out of the box, but only JTA is supportedTransaction management

SpringEJB 3

The Matrix: EJB3, Spring and Hibernate

EJB 3 is the true path…right!?

My boss wants me to use Spring.

Is there a peaceful co-existence?

Spring and EJB 3 Integration

Spring-enabled Session Beans

@Stateless

public class PlaceBidBean extends

AbstractStatelessSessionBean

implements PlaceBid {

private BidServiceBean bidService;

protected void onEjbCreate() {

bidService =

(BidServiceBean)

getBeanFactory()

.getBean("bidService");

}

public Long addBid(Bid bid) {

return bidService.addBid(bid);

}

}

Accessing EJB from Spring Beans

public class ItemServiceBean implements

ItemService {

// Setter injection of ItemManagerEJB

public void setItemManager(

ItemManager itemManager) {

this.itemManager = itemManager;

}

public Long addItem(Item item) {

Item item =

itemManager.addItem(item);

..}

}

<jee:jndi-lookup id = "itemManager"

jndi-name = "ejb/ItemManager"

resource-ref = "true"/>

EJB 3 features in Spring

• Spring Pitchfork project provides partial support of EJB 3

• Supports EJB 3 Annotations

– Annotations such as @Stateless, @Resource, @Interceptors are used

MDB and Spring JmsTemplate

Simplified JMS Client

with JmsTemplateRobust message

consumer with EJB 3 MDB

EJB 3 and Spring : The Bottom Line

• Use EJB 3 if you:

• Like annotations and dislike XML

• Prefer a tightly integrated solution stack that makes sensible default choices for you

and minimizes configuration.

• Your application is very stateful.

• Standardization is an important consideration.

• JSF and are considering frameworks such as Oracle ADF, JBoss Seam.

• Use Spring if you:

• Want your application to be portable across platforms not supporting EJB 3

• Want to build your own solution stack (such as with iBATIS, Quartz or Acegi).

• Need advanced AOP features.

•Your application requires a lot of configuration beyond gluing together components

and resources.

Summary

• Both EJB 3 and Spring can be used complimentary technology together

Resources

• Spring and Java EE : Simplicity and Power Combined (JDJ articles http://java.sys-con.com/read/393298.htm

and http://java.sys-con.com/read/366297.htm )

• Spring Framework (http://springframework.org/)

• OTN Spring Resource Center:

http://otn.oracle.com/spring/

• EJB 3 In Action (http://manning.com/panda)

• Spring in Action

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Shameless Marketing plug

http://manning.com/panda

http://debupanda.com

spring and ejb 3: all-star team or neighbors with good fences

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